#include <stdio.h>
#include <stdlib.h>
#define DOUBLE(x) ((x) * (x))
#define PLUS(x) ((x) + (x))
#define ADD_TO_SUM(sum_number, value) \
    sum##sum_number += value
// 宏函数
#define MALLOC(size, type) \
    (type *)malloc((size) * sizeof(type))
    // 条件编译
#define LETTER 0

void function01();

int main()

{
    int sum5 = 1;
    ADD_TO_SUM(5, 10);
    printf("%d \n", sum5);
    printf("%d \n", DOUBLE(sum5 + 1));
    printf("%d \n", 2 * PLUS(sum5 + 1));

    int *p = MALLOC(25, int);

    if (p != NULL)
    {

        printf("%p 开始地址\n", &p);
    }
    else
    {
        printf("没有分配");
        exit;
    }
    function01();
}
// 条件编译
void function01()
{
    printf("ggg");
    char str[20] = "C Language", c, *b;
    // 用指针遍历数组
    b = str;
    int i = 0;
    exit;
    while ((c = *(b++)) != '\0')
    {
        i++;

#if LETTER
        if (c >= 'a' && c <= 'z')

            c = c - 32;

        else if (c >= 'A' && c <= 'Z')

            c = c + 32;

        printf("%c", c);
#endif
    printf("啥事都不干");
    }
}